Fluid distributing valve



Patented Mar. 14, 1950 FLUID DISTRIBUTING VALVE George I. Chinn, Baltimore, Md., assignor to Gerotor May Corporation, a corporation of Maryland application July 15, 1947, Serial No. 761,043

4 Claims.

An objectof my invention is the provision of a simple, reliabl and highly practical automatic load control valve which effectively distributes fluid power supply to' one or more hydraulic motors as a function of motor load encountered during the course of operation.

A further object of my invention is the provision of a compact and eflicient hydraulic multiple motor system in'which fluid is reliably distributed to appropriate motors in accordance with motor output power demands encountered, and which system is well balanced, and positive in operation throughout the several intended stages of use.

Other objects and advantages in part will be obvious and in part pointed out hereinafter.

The invention accordingly consists in the combination of elements, features of construction and arrangement of parts and the relation of each of the same to one or more of the others as described herein, the scope of the application 7 Figure 2 shows a different operating position of the valve as compared with Figure 1; and

Figure 3 represents a still further operating portion of valve as compared with the previous figures.

As conducive to a clearer understanding of certain features of my invention, it may be noted at this point that frequent recourse is had in the prior art to a variety of types of hydraulic motors and the like which are required to adapt themselves to varying load factors, this illustratively being in any of a wide range of industrial arts and sciences, as in the instance where planers, lathes, or milling, pressing and stamping machines are operated. These machines often are subjected to a considerable range of loading. Under certain conditions heretofore known, anticipated peak loads on the machines have been accounted for by the installation of a single motor of suflicient capacity. This often has resulted in a high initial cost of installation, as

cutting in or out the additional power is confronted. At times, this involves supplying fluid as to a single hydraulic motor wher the load is commensurate, and where an overload is encountered a problemdcvelops of introducing a supplyof fluid to an aiding motor or motors for sharing the load until conditions are appropriate for returning to single motor operation. Without some automatic shifting arrangement which is responsive to motor load, reliance must be had upon the discretion of an attendant for keeping the proper number of motors running under load. A shift back to the single motor, however, whether automatic or manual, if effected at an inappropriate time in view of the load often is responsible for such difficulties as inefficiencies, breakdown and wear from repeatedly imposing an overload and reat stress on the single engine..

An outstanding object of my invention accordingly is th provision of a simple, practical and reliable multiple hydraulic motor system having highly effective automatic distributing valve control over the motors therein in accordance with varying motor power demands, and which system is easy to install and maintain in satisfactory operating condition.

Referring now more particularly to the practice of my invention, an embodiment of the hydraulic distributing valve which I provide will first be described. This embodiment represented by the valve 5 (see Figure 1) comprises a casing III which for example houses two interfitting plungers II and I2 for controlling a fluid power supply. The plunger ll is a fundamental plunger, illustratively an overload relief plunger, which has an offset end lip l5 fitting into a cylindrical bore M of the portion Illa of the casing and abutting inset l3 of this portion of the casing. A head element Nb of the valve casing receives the other end of the plunger II in a cylindrical bore I6, this head element being adjustably secured by threads I! to the inner surface of the casing portion Illa and sealed fluidtight by the same, for example byflmeans such as a sealing ring or packing I 8.

'Thereis a compartment or clearance space 2| defined between the head element Hlaand plunger 'inafter described. ring I9 between the plunger. and bore surface of II, this for permitting sliding movement of the latter to a suflicient extent for the purpose here- I usually employ a sealing the head element, for ensuring against fluid leakage. An air vent 22 leads from the compartment 2! to the atmosphere for enabling free movement of the plunger.

, A coil spring 20 is compressed betweenthe innermost end of the head element lllb and the adjacent surface of offset lip I5 of the plunger, for

pressing this lip to a seating relation against.

j lip l of the overload relief plunger.

ano es? inset ll of the casing. The compression of this spring conveniently is adjusted by screwing or unscrewmg' the threads II. To account for any 1 adjustment of the threads. the packing means I8 usually is changed, or reset by suitable means not shown.

l The valve casing in has a plurality of fluid openings through the body thereoflfor example, these being an inlet port 50, and outlet ports 5|, 52 and 53.

certain conditions to be more fully exempli- 1 fled hereinafter, one Or both of the remaining 1 outlet ports 52 and 53-are opened to the chamber 54 by control plunger |2 or are substantially 1 closed oil by the latter. 'An end portion |2a of i this control plunger confronts the valve inletv opening 50 and under conditions of relatively low fluid pressure in the chamber, seals against an j annular seat 55 formed in the casing'wall at The imet port leads into a fluid re- 1 ceiving chamber 54 which preferably is constantly in open communication with the outlet 1 port 5| for an'ording a fluid outlet supply. 1 Under 5 4 tion indicated in Figure 2. It will be observed that inthis position the end area Me of the control p unger is masked against the pressure enect of nuld, and that the bleed line lzd empties directly into port ||c of the overload relief plunger, the bleed-on chamber 56 being substantially nonexistent. Also of further significance, wltntne control plunger in this position, both of the outlet ports 5| and 52 are open for discharging fluid from the receiving compartment 54. Both of the plungers, while in the position indicated in Figure 2, are ready for unitary displacement against the action of coil spring 20 to the. position points between outlet ports 5| and 52, and thus constitutes a wall of the chamber. The opposite end portion |2b of the control plunger, this being l remote from the valve seat 55, fits for sliding 5 movement in a substantially cylindrical bore 51 1 in the body of the overload relief plunger II and accordingly forms fluid bleed-off chamber 55 with the same. The control plunger has a reduced diameter portion |2c intermediate the ends thereof which is guided by the inner surface of end A coiled spring 60 surrounds the reduced diameter portion and is compressed between the lip 5 and the back 1 of portion |2a of the control plunger, thus posi- 3 tively urging this plunger away from the overload j relief plunger and against the annular valve seat 1 55. The spring is relatively weak, as compared with the coil spring 20 which resists displacement of the overload relief plunger Control plunger l2 has a longitudinal bleed line |2d extending through the body thereof and interconnecting the receiving chamber and bleedof! chamber of the valve.

One function served by this bleed line, during certain phases of operation of the valve, is that of admitting fluid under pressure to the bleed-oil chamber and against end area 2e of the .control plunger, thereby partly or fully counteracting the efiect of substantiallythe same unit fluid pressure against the plunger end area l2 The end areas 2e and I2! preferably are of substantially the same efiective size for receiving a like total pressure and thus hydraulically balancing the control plunger under varying unit pressure conditions within the limits of closure of bleed-oil valve llb, full reliance for example being had upon the force of coil spring for loading the control plunger to closing position against seat 155. r

The bleed-oil valve lb is a pressure responsive valve in the overload relief plunger l2 and serves to close bleed-off chamber 56 so long as a certain pressure in the chamber is not exceeded. An ad- Justing means ||h usually is provided for varying the pressure limit of close-ofl'. The bleed-oil valve controls outlet port He in the overload relief plunger and also fluid line (I leading from the valve through the plunger to outlet 53 in the casing portion la.

The overload relief plunger II and control plunger l2} respectively have protruding annular lips llg, |2g which nest one within the other when the control plunger is displaced to the posi- 'motor operating system, this including the hy- Jdraulic distributing valve 5, is schematically represented in Figure 1. This system comprises two rotaryhydraulic motors, the motors 'llland ll, both having their rotors .connected to power take-ofi shaft 16 for driving the same. The rotary hydraulic motor 10 has a suflicient horsepower rating to drive the shaft 16 throughout a first stage of operation until a certain high load condition of the shaft is reached, after which, in a second stage of operation, the motor 1| will share the load.

To supply the necessary hydraulic fluid for motor operation, I usually employ a suitable'hydraulic pump 12, such as a constant delivery rotary pump, this having an intake line 80 illustratively from reservoir 13 which contains the supply fluid. The output or pressure side of the pump is interconnected by conduit 8| with inlet port 50 of the distributing valve 5 and thus with the valve chamber 54 where the fluid is received.

Outlet ports 5| and 52 of the valve are connected by fluid lines, I4 and 15 respectively to the high pressure or inlet sides of the motors l0 and II. There are outlet lines 11 and I8 individually leading from the respective hydraulic motors. These outlet lines connect into a conduit I9, which extends from outlet port 53 of the valve Hi to the fluid supply reservoir 13 and bypasses the inlet sides of the motors. A ball check valve 58, as for example disposed in the body of the casing of valve 5 between the outlet ports 52 and 53, conveniently safeguards against the pumping of air by the motor 1| during the second stage of operation of the hydraulic system.

Assuming now that the hydraulic pump 12 is operatively pumping fluid from reservoir 13 through conduits 80 and 8| to receiving chamber 54, and that control plunger I2 is in the initial position represented in Figure l, the fluid leaves the valve through outlet St and conduit 14 and passes to the motor Ill. This fluid drives the motor, thus causing a rotation of the shaft 16, and returns through conduits 11 and 19 to the reservoir 13. At the outset of this distribution, the bleed line |2d in control plunger |2 admits fluid to bleed-off chamber 56, where hydraulic pressure is exerted on the plunger end area I2e and is resisted by the bleed-off valve ||b 1 relation with seat 55 by counteracting pressure exerted on plunger area |2j while the motor 10 is in first stage operation. Under these conditions, fluid in the receiving chamber 5! is eflectively blocked, by the control plunger, from outlet ports 52 and 53. The motor ll therefore does not aid in driving'the shaft I6 at this time; instead, the motor idles under the driving action of motor 10 and tends to suck air. The sucking of air advantageously is avoided, for example by using a ball check valve 82, which impedes the return of fluid through conduit I9 to the reservoir 13 by an amount suflicient to back up fluid in the conduit to ball check valve 58 thereby opening the same and filling the line 15 leading to motor II. This fluid accordingly satisfies the volumetric capacity of the idling motor and feeds through line lt tq the conduit 19 for recirculation through theyalve 58 or for return to the reservoir. f

When the motor 10 begins laboring under an excessive load, 'this is hydraulically reflected by an increase in back pressure in the line 8| and receiving chamber 54. The pressure increase also is transmitted through the fluid in bleed line Md and bleed-off chamber 56 to bleed-off valve llb. Where this pressure reaches a certain value, say for example 900 pounds per square inch, outlet He is opened by the valve lib resulting in the escape of fluid from bleed-off chamber 56 through bleed line Id to the by-pass conduit 19. As this escape progresses, there is a lowering of pressure in the chamber 56 as compared with the pressure still exerted on end face [2 of the control plunger I2. When pressure in chamber 56 reaches a certain low value, the coil spring 60 is no longer able to resist the force .of fluid on plunger face I21. The control plunger l2 accordingly is unseated from the seat 55 thus enlarging the chamber 54 and opening the latter to the outlet port 52. The unseating displacement of the control plunger is stopped by abutment of this element with the innermost end of bore 51. in the overload relief plunger l2. In this position (see Figure 2) the end area [2e of they plunger preferably is partly or wholly masked from the effect of fluid pressure, the masking illustratively being by the overload relief plunger as by abutment with the lip 12g. The annular lip Hg nests into the annular lip I29 and preferably falls short of abutment with the control plunger I! so as to leave an effective portion of the end area He uncovered, this facilitating return of the plunger to seat 55 under appropriate pressure conditions.

The outlet 53 is still blocked by the plunger l2 against thedirect passage of fluid from receiving chamber 54. While the bleed-off valve remains open under the high pressure conditions, however, fluid passes through bleed line Md and directly into the outlet opening Ho and thence through the valve and bleed line I Id and line 53 to the motor by-pass conduit I9. The main distribution of fluid coming from the pump to the receiving chamber 54, nevertheless is through the outlet ports 5| and 53, through the respective conduits l4 and I5, and into the motors Ill and II. Both of the motors thus are hydraulically driven in an aiding direction and accordingly share the load of the shaft I6. The fluid leaves the motors through lines 11 and I8 and returns through conduit 19 to the reservoir 13.

When the power demand has been met by the combined operation of the motors, the pressure in receiving chamber 54 drops, and control plunger I! returns to abutment against seat 55, thus closing the outlet port 52 and cutting out the motor II. The hydraulic distributing valve usually is made for reverting from multiple motor feed to single motor feed at a considerably lower pressure than is required to initiate the multiple feed, this for example by proper masking" of one end of the control plunger and by appropriate strengthof the spring 66 and appropriate resistance to opening by the bleed-off valve llb. This ensures ample running speed of the motor shaft 16 before going back to single motor operation. I usually employ small grooves llh in the bore wall of the overload relief plunger and an inset l2h in the annular lip I29. The inset and grooves serve to pass liquid between chambers 54 and 56 to improve pressure conditions, such as by relieving vacuum, when control plunger moves immediately in the vicinity of the annular lip Hg.

With the end area l2e of the control plunger entirely or artially masked during combined operation of the motors, the return to single motor operation depends upon a considerable drop in pressure in the receiving chamber 54, say to 500 pounds per square inch. This low pressure on the plunger face |2f enables the coil spring 66, acting alone or together with hydraulic pressure on any unmasked portion of the face l2e, to start the control plunger toward seating position for single motor operation. The bleedoff line I 2c and bleed-off chamber 56 then become active for supplying fluid to the entire plunger face In which exerts a pressure in favor of seating the control plunger. Outlet port 52 accordingly is closed and single motor operation ensues until pressure in the bleed-ofi chamber 56 again becomes sufflciently high (illustratively 900 pounds per square inch) as to open the valve ,l lb.

In the event an extreme load, beyond the capacity of both of the motors, is thrown upon shaft 16 the overload control plunger l I until that time serving as a stop for the control plunger I2 is displaced for by-passing fluid around the motors. This displacement is effected by an increased back pressure from the motors on area I2j of the control plunger (say for example 1000 pounds per square inch), and is prevented at lower back pressures by the coil spring 20. Under the increased pressure, control plunger l2 stops against the overload relief plunger and transmits the hydraulic force on face l2j to the same. The overload relief plunger then retracts in bore l6, againstvspring 20, the retraction being suflicient (see Figure 3) 'to carry the control plunger I! clear of outletport 53. Fluid supplied from the pump 12 then passes through port 53 and conduit ls back to the reservoir 13, thus by-passing the motors and saving undue stress on the system. Under favorable pressure conditions in chamber 54 the overload relief plunger returns to the position occupied during normal operation of the system (see Figures 1 and 2).

A selective distribution of fluid therefore is automatically achieved in the fluid system of my invention upon variations in the motor working load being reflected'by predetermined increase or decrease in the input pressure on the motor or motors, whether for example the motors be of the rotary type or reciprocative rams. This selective distribution supplies working motor units or other hydraulic mechanisms, whether the units are connected or are independent of the power output of each other. Further, when a maximum torque or other load is reached, the hydraulic input pressure is automatically relieved, by a byremains until conditions are corrected, avoiding damage to the system.

The automatic hydraulic distributing valve makes possible the use of like or-widely different power units with regard to volumetric consumption and power rating of each. The valve is readily installed so as to operate eflectively and continuously for long periods of time with a minimum of supervision, adjustment and expense. During operation the valve appropriately distributes a dependable power head to each motor and ensures adjustment of the system for varyin loads.

'Thus it will be seen that in this invention there are provided a distributing valve and a hydraulic motor system in which the various objects hereinbefore noted together with many thoroughly practical advantages are successfully achieved. It will be seen that the system readily adjusts itself for efllciently and economically meeting varying torque or other load. conditions encoun:- tered by the hydraulic motor or motors. It will be seen also that the distributing valve is simple, practical and reliable, and is well suited for supplying fluid from one or more outlets as prompted by different pressure conditions.

While my distributing valve is described herein as serving the useful function of admitting fluid to a certain motor by-pass line during conditions of motor overload, it will be understood that at thus 'times this line instead has a motor connected therein as for aiding the other motors already described.

As many possible embodiments may be made of my invention and as many changes may be made in the embodiment hereinbefore set forth, it will be understood that all matter described herein is to be interpretedas illustrative-an not as a limitation.

I claim as my invention:

1. A fluid distributing valve. comprising, in

combination, a casing having an inlet and aplurality of fluid distributing outlets, stop means within said casing and biased for yielding to force applied beyond a certain limit of resistance, an outlet control plunger in the casing and normally advanced from said stop means to close at least two of said fluid distributing outlets substantiallyfrom said inlet and having opposing end areas susceptible to substantially the same unit pressure, and means for relieving pressure in excess of a certain value from one, plunger end area for setting up a sutlicient pressure differential todisplace the plunger to abutment with the stop means and thus opening at least one of said closed fluid outlets, said plunger in the abutting position being susceptible to fluid pressure exceeding the certain limit of resistance of said stop means for unitary displacement with the latter element to open at least another of said fluid outlets.

-2. A- fluid distributing valve, comprising. in combination, a casing having an inlet and a plurality of fluid distributing outlets, stop means within said casing and biased for yielding to'force applied beyond a certain limit of resistance, an

outlet control plunger in the casing and normally advanced from said stop means to close at least two of said fluid distributing outlets substantially from said inlet and having opposing end areas susceptible to substantially the same unit pressure, and means for relieving pressure in excess of a certain value from one plunger end'area for setting up a suflicient pressure difl'erential to displace the plunger to abutment with the stop means and thus open at least one of said 'closed'fluid outlets, said plunger in the abutting position belng'at leastpartially masked at the pressure relieved end area by said stop means and susceptible to fluid pressure for efiecting unitary movement with the same to open at least another of said fluid outlets.

3. A fluid distributing valve, comprising, in combination, -a casing having an inlet and a plurality of fluid distributing outlets; a reciprocative fundamental plunger received within said casing and biased at one end for yielding to force applied beyond a certain limit of resistance to the opposing end; a reciprocative outlet control plunger in the casing substantially closing oil at least two of said outlets and having opposing end faces respectively adjacent to a fluid receiving chamber at said inlet and a fluid bleed-oil! chamber at the bias-opposing end of the funda-* mental plunger, said chambers being interconnected by a bleed line; and means-for relieving fluid pressure in excess of a certain value from the bleed-off chamberfor setting up a suflicient pressure differential across the opposing ends of said control plunger to displace the latter to abutment with the fundamental plunger and thus open at least one of said closed fluid outlets, said control plunger in the abutting position being susceptible to fluid pressure in the receiving chamber exceeding the certain limit of resistance of said fundamental plunger for unitary displacement with the latter element to open at least another of said fluid outlets.

4. A fluid distributing valve. comprising, in combination. a casing having an inlet and a plurality of fluid distributing outlets: a reciprocative fundamental plunger received within said casing and biased at one end for-yielding to force applied beyond a certain limit of resistance to the opposing end; a reciprocative outlet controlplunger in the casing substantially closing oil at least two of said outlets and having opposingend faces respectively adjacent to a fluid receivingchamher at said inlet and a fluid bleed-omchamber at the bias-opposing end of the fundamental plunger, said chambers being interconnected by a bleed line extending through the body of the control plunger; and a pressure relief valve and bleed-oil line controlled by the same, in said fundamental plunger for relieving pressure in excess of a certain value from said bleed-off chamber for setting up a sufficient pressure diiferential across the opposing ends of said control plunger to displace the latter to abutment with the fundamental plunger and thus opening at least one of said closed fluid outlets; said control plunger in the abutting portion being at least partially masked at the pressure relieved end and susceptible to fluid pressure in the receiving chamber exceeding the certain limit of resistance of said fundamental plunger for unitary displacement with the same to open at least another of said fluid outlets.

GEORGE I. CHINN.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Bonnell Nov. 13, 1945 

